Pump impeller



Nov. 14, 1944. J. KUTTNER 2,362,703

PUMP IMPELLER Filed Aug. 21, 1942 2 Sheets-Shget 1 F I- w /A/l EA/7'O JUL /u5 KuTn/EE,

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J. KUTTNER Nqv. 14, 1944 PUMP IMPELLER Filed Aug. 21, 1942 2 Sheets-Sheet 2 Patented Nov. 14, 1944 UNITED. STATES PATENT orrlcs PUMP IMPELLER .luliuslluttner, Beloit, Wis., assignor to Fairbanks, Morse & 00., Chicago, -Ill., a corporation of Illinois Application August 21, 1942, Serial No. 455,601

'1 Claims.

power required to operate the vane. According to the present invention, the vane is constructed from an alloy known to the trade as Dow Metal, wherein the allow has a predetermined composition particularly adapted to theformation of an oscillating pump vane.

Another object is to provide a novel and eflfective shaft mounting arrangement for the vane, which will afford a secure operating connection between the vane and its drive shaft.

Other objects and advantages attained by the present improvements will appear readil from the following description and accompanying drawings. In the drawings:

Fig. 1 is a view in sectional elevation, of a fluid pump illustrating the presently improved impeller vane therein;

Fig. 2 is a fragmentary sectional view of the pump and vane, as taken along the line 22 in Fig. 1;

Fig. 3 is an end elevation of the improved iin peller vane;

Fig. 4 is a longitudinal sectional elevation thereof, as viewed from line 4-4 in Fig. 3;

Fig. 5 is a transverse section of the vane, as

taken along line 5-5 in Fig. 4;

Fig. 6 is an end view of the vane, similar to view of Fig. 3 but taken at the opposite end thereof, and

Fig. 7 is a'longitudinal section through the vane hub, as taken along the line 'Il in Fig. 4.

Referring to the drawings by appropriate characters of reference, there is illustrated by Fig. 1 a

fluid pump denoted generally by the numeral l0,

in which is embodied the improved oscillating vane or impeller ll forming the subject of the present invention. Although the vane may be employed in pumps serving various purposes, the

pump as shown herein, is of a character suitable for use with internal combustion engines to supplyscavenging air to the engine cylinders. Since apart from the vane and its mounting on pump shaft indicated at l2, the form and structural details of the pump do not concern the one-way valves 24 from supply chambers 25 in the present invention, such will be described only The pump i0 which is illustrated somewhat diagrammatically, includes a casing structure designated generally by the numeral i4, providing a fluid chamber ii in which the vane ll oscillates. The chamber is divided by casing par- I titions l6 and fluid seals II between the partitions and the hub portion I18 of vane ii, to pro vide opposite pumping compartments I9 and 20 one for each of the vane arms 22. Communicatingwith the compartment is on the opposite sides thereof, are passages 23 which serve alternately as inlet and outlet passages for the compartsnent. Fluid as air, is admitted to the passages 23 on the suction strokes of the vane arm 22 in compartment i9, through unidirectional or communication with the atmosphere or other source of air. The air thus drawn into compartment is alternately on opposite sides of the vane arm 22, is discharged therefrom alternately into the passages 23 in response to the compression or discharge strokes of the vane arm, and thence through similar one-way valves 26 into a chember 21,- from which the air under pressure may be conducted to the engine cylinders. Similar passages 28 are associated with the other pump compartment 20, and include inlet valves 29 and outlet valves 30 providing respectively, one-way communication between the supply chambers 25 and the passages, and between the passages and a dischargechamber 32 which is similar to the discharge chamber 21.

With reference now to the improved oscillating impeller II, this member is constituted by a unitary casting of a light weight, relatively soft metal alloy known to the trade as Dow Metal, wherein the alloy has a composition especially suited to the formation of the impeller or vane,

so as to aflord a strong yet light-weight impeller having a desirably low moment of inertia. The alloy composition employed for this purpose, consists of the following elements in the proportions portance to the present attainment of a vane having a desirably low moment of inertia.

The improved vane structure as shown particularly by Figs. 3 to 7, comprises a hub l8 of generally, tubular form, and integral vane arms 22 extending radially from diametrically opposite sides thereof. shown, providing'imperforate side walls 33 joined by a wall 34 at the forward or tip end of the vane, and end walls 35 each apertured as at 35. The tip wall 34 may be rounded as shown, in conformity with the wall curvature of the pump chamber I in which the vane operates (Fig. 1). Within the hollow arm are a series of transverse partitions or webs 3'! each by preference apertured at 38, these members serving to strengthen the vane arm and in particular, the side walls 33 thereof. As will be observed from Figs. 1, 3 and 5, each vane arm is appreciably tapered from the hub l8 convergently toward the tip wall 34, which with the removal of metal in the end walls 35 and partitions 31 in zones inwardly from the tip end of the arm, as to provide the respective apertures 35 and 38, thus serves to determine or locate the Each arm is of hollow form ascenter of mass of the arm nearer the vane axis of oscillation. This last is a factor of importance to the attainment of a vane structure having a relatively low moment of inertia, as will be appreciated.

According to the present improvements, provision is made for effecting a positive and durable driven connection of the alloy vane to the shaft t2 the means for attaining this end being of a character to avoid direct key-connection between the shaft and the vane hub l8, which would rrquire the provision of a substantially narrow and deep longitudinal slot or key-way in the relatively soft metal of the hub. As herein provided, a number of similar bushings 39 are integrally united with the hub l8 in the casting of the vane structure, which bushings are of suitable, hard material, as steel, each having key-ways 40 to receive keys 42 in the connection thereof to the shaft 12. The rigid cast connection of the bushings-and vane hub I8 is assured in a most effective manner. by the provision of opposed, rounded projections or lobes 43 on each bushing 39, which seat in correspondingly curved hub recesses 44 formed in casting the impeller with the bushings. In this manner, the bushing is integrally keyed to the vane hub such that the shearing forces in these zones resulting from rapid oscillation of the shaft and impeller, are desirably distributed to an extent such as to substantially preclude cracking of the soft metal hub l8.

The shaft I2 is projected through the hub bore 45 as shown by Fig. 2, to seat in the bushings 39, and is keyed to the latter elements by the keys 42. A raised shaft portion 41 formed inwardly adjacent the shaft end 48 which extends beyond the vane end 49, is closely received in a' bearing seat 50 provided by an internal annular extension or projection 52 of the hub I8 at the vane end 49. In order to secure the vane structure against displacement longitudinally of the shaft, the latter is provided with an annular flange 53 near the shaft end 54, which seats in an annular recess'55 formed in the exposed edge 56 of the bushing 39 at the end 51 of vane'hub l8 (Fig. 2). On the opposite end 48 of the shaft I2 is provided a collar 58 which abuts the hub projection 52 in a recess 59 formed therein. With the bushing 39 at the hub end 51 in firm abutment with the shaft flang 53, the collar 58 is clamped against the hub projection the vane along the shaft I2 is thereby effectively precluded.

In the support of the vane shaft l2, the shaft bearing 52 above indicated, is received in a mounting socket or recess 63 formed centrally in one end wall 64 of the pump casing, while the opposite casing end wall 55 is provided with a projecting bearing support 56 carrying a sleeve bearing 51 for the end-5 4 of shaft l2. The shaft end 54 is extended outwardly beyond the bearing 51 to provide for driving connection to the oscillating vane, as from an operating part of the engine (not shown) with which the pump may be associated.

As will now appear, the present improvements concern the formation of an oscillating pump vane or impeller from light-weight Dow Metal alloy of the composition indicated, and the impeller connection to its operating shaft, whereby to characterize the vane by a relatively low moment of inertia, and by'a strong and durable structure having a positive connection to its operating shaft, with the latter effected in a manner to avoid key-way slotting of the soft metal vane hub.

Having describeda preferred embodiment of the present invention, the features thereof desired to be protected by Letters Patent are set forth in the following claims.

' the impeller comprising a substantially tubular hub, shaft-engaging bushings arranged in the hub, and impeller arms extending radially from said hub, said hub, arms and bushings being integrally united to form a unitary structure.

3. An impeller of the character described, for a fluid pump having an impeller actuating shaft, the impeller comprising a cast metal structure including a tubular hub having radially opposed vanes projecting therefrom, and a bushing adapted for connection to the shaft, embedded in said impeller hub, said bushing having projecting icicles thereon, seating in recesses therefor in the .4. An impellerof the character described, for a fiuidpump having an impeller actuating shaft, the impeller comprising a cast metal structure including a tubular hub and radially opposed vanes projecting therefrom, and a bushing adapted for connection to the shaft, provided with arcuate projections thereon, said bushing being.

integrally united with the hub in the casting of the impeller, with said arcuate projections seatgigb in correspondingly arcuate recesses in the 5. An impeller of the character'described, for I hub, shaft-engaging bushings arranged in the hub, and impeller arms extending radially from said hub, said hub and arms being formed as an integral structure, from a relatively soft, lightweight metal alloy, with said bushings embedded in said hub.

6. An impeller 01' the character-described, for a fluid pump having an impeller actuating shaft, the impeller comprising a substantially tubular hub, shaft-engaging bushings embedded in said hub, impeller arms extending radially from said hub, each thereof being of hollow form, and transverse strengthening elements within each arm.

7. An impeller for a fluid pump having an impeller actuating shaft, comprising a unitary structure including a tubular hub, shaft-engaging bushings arranged in the hub, and impeller arms extending radially from the hub, said impeller hub and arms being formed from a relatively soft, light-weight metal alloy containing about ninety percent magnesium, and the impeller further being characterized by a relatively low moment of inertia.

JULIUS KU'I'INER. 

